The present invention relates to an aeration valve for drink cans. In particular, the present invention relates to aeration valves advantageously used for approximately five liter cans containing a liquid such as, for example, beer.
Conventional five liter drink cans, which can have a laterally positioned emptying tap, are known to include aeration valves that are insertable in an upper bunghole. The aeration valves typically include a valve insert formed as one piece and an elastic bung socket also made in one piece with a sealing bead cooperating with the valve insert, a projection serving for the support on the edge region of the can lid surrounding the can opening, a sealing surface present below the projection and cooperating with the edge of the can opening, as well as a support gripping behind the edge of the can opening.
The bung socket has a lateral aeration opening on the section directed into the inner part of the can. The valve insert is rotatably mounted and can be moved between an xe2x80x9copenxe2x80x9d and a xe2x80x9cclosedxe2x80x9d position, whereby the aeration opening is opened or closed.
One disadvantage of known aeration valves is that the bung socket is completely made of elastic material and, therefore, it is difficult to provide a valve that may be operated to selectively seal a drink can under pressure.
A further problem associated with the introduction of the known aeration valves into the bung hole of the cans results from the projection being formed from a soft material. The soft material can give way when the valve is forced into position so that the entire valve is pressed into the can.
In the case of the known aeration valves, a lip formed on the valve insert engages two recesses formed in the projections of elastic material which are provided for the determination of whether the valve is in the xe2x80x9copenxe2x80x9d or closedxe2x80x9d position. In addition, a projection arranged in the interior of the bung socket, together with the edges of a recess in the valve insert, serves as a mechanical stop for the determination of the xe2x80x9copenxe2x80x9d or xe2x80x9cclosedxe2x80x9d position.
A disadvantage of this valve structure is that, during the rotational movement of the opening procedure, the lip on the valve insert projects into the material of the projection and deforms the projection, thus making the opening procedure more difficult. The performance of the stop is limited by the elastic material of the projection in the interior of the sleeve. As a result, turning of the valve insert too far cannot be prevented.
It is not possible to determine the exact starting and end points of rotary movement of the valve insert. Thus, an exact opening and closing of the valve cannot take place. Due to the structure of the mechanical stop, the valve insert has a complex geometric form which leads to high production costs. In addition, the complex form only permits the valve insert to rotate in one direction.
Furthermore, as disclosed in German Patent No. DE 3345619, bung hole closures are known which serve for receiving dispensing fittings with tapping pipes and can also be used for the aeration of drink cans because an integrally formed plate is penetrated.
One disadvantage associated with the use of a lateral emptying cock or of a dispensing fitting without a tapping pipe, is that the penetration and thus the aeration of the drink can cannot take place without the use of an auxiliary means or a firm object such as, for example, a key or screw driver.
It is a further disadvantage that, in the case of drink cans which are equipped with known aeration valves and a lateral emptying cock, it is not possible to use a dispensing fitting with a tapping pipe.
The present invention provides an aeration valve having optimal sealing, and relatively simple and exact aeration of drink cans, while also making possible the use of a dispensing fitting having a tapping pipe.
According to the present invention an aeration valve for a can is provided. The aeration valve includes a sleeve configured to be inserted into a top opening of the can, the sleeve including an inner wall surrounding an axial bore, a top surface facing generally away from the can when the sleeve is inserted, and a lateral bore positioned on a lower portion of the sleeve adapted to be inserted into the can. The valve further includes a rotatable insert positioned within the axial bore, the insert including a plate, a projection formed centrally on the plate, and a holder in which the projection engages. The projection includes a first flat surface in a spaced apart relationship with the inner wall to form a first channel therebetween. The holder includes a first sealing surface adapted to mate with the inner wall of the sleeve to thereby seal the lateral bore and a second flat surface in a spaced apart relationship with the inner wall to form a second channel fluidly connected to said first channel. The plate extends over the top surface of the sleeve and includes a bottom surface overlying the top wall and including a first recess fluidly connected to the first channel and an exterior of the valve, so that when the insert is rotated to position the second flat surface opposite the lateral bore, the interior of the can is aerated through the second channel, the first channel and the first recess.
Preferably, the bottom surface of the plate includes a cam which engages a second recess located in the top surface of the sleeve. The sleeve preferably includes a bottom plate closing the end of the axial bore that is configured to be inserted into the can, where the bottom plate has a predetermined breaking point. The bottom plate may alternately include a stopper capable of being held by clamping action. The holder preferably includes a cutting edge directed toward the bottom plate of the sleeve and engages the predetermined breaking point in the sleeve.
The holder preferably further includes a radial guide member located on a lower side. Preferably, the radial guide member has a diameter corresponding substantially to the diameter of the axial bore of the sleeve and includes a recess on a lower side of the holder that engages an upwardly projecting extension of the bottom plate. The holder preferably includes a second sealing surface and a third flat surface.
The projection preferably includes radial guide members which cooperate with a sealing bead located on the inner wall of the sleeve. The plate preferably includes a tab that is, preferably, connected to the plate via hinges. The top surface of the sleeve preferably includes a cut-away edge having a downward sloping opening that engages the tab.